My question involves powering an Arduino Uno through the Massoth decoder on a locomotive. Is this possible? I've tried several sockets on the decoder, which resulted in short circuits. I'm worried I will fry it. Has anyone had any luck with this?
Your Uno requires a regulated 5v supply. The Masoth decoder boards are designed to drive locomotive motors and have a variable supply voltage up to 24v, will be capable of providing a high current on demand, and will likely produce a lot of switching noise. These are simply not designed for applications where a fixed stable voltage is required.